MELBOURNE, Australia — American Serena Williams tumbled to the court and needed a medical timeout in the first set for treatment on her right ankle Monday. Once she got up, it was all over for Edina Gallovits-Hall of Romania.

Williams routed Gallovits-Hall 6-0, 6-0 in the first round of the Australian Open tennis tournament despite the scary sequence in the first part of the match.

The third-ranked Williams is favored to win the season’s first major, rolling into Melbourne Park with 35 victories in her previous 36 matches, including titles at Wimbledon, the London Olympics and the U.S. Open.

But the injury might be a setback as she seeks a third consecutive title in a Grand Slam tournament.

Kimiko Date-Krumm, a 42-year-old from Japan, upset No. 12 Nadia Petrova of Russia 6-2, 6-0 to become the oldest woman to win a singles match at the Australian Open.

Andy Murray of Britain won his first match as a Grand Slam tournament champion, beating Robin Haase of the Netherlands in straight sets. Second-seeded Roger Federer of Switzerland defeated Benoit Paire of France in straight sets.

Williams was leading 4-0 after 19 minutes when she fell awkwardly chasing a ball wide on her forehand side.

She rolled from her back to her hands and knees, where she stayed for several minutes before she was helped to her feet.

“I think I was really, really close to panicking because a very similar thing happened to me last year, almost on the same side, the same shot,” Williams recalled.